8 / 10

1. Place cups in shallow baking pan. Spoon watermelon puree into cups, dividing equally (scant 3 tablespoons each). Freeze until mixture is almost frozen, about 2 hours. Cover cups with rounds of foil, sealing tightly at edges. Using tip of small knife, make 1/4-inch slit in center of each foil cover. Push ice pop stick through slit and securely into watermelon ice without hitting bottom of cup. Freeze until watermelon ice is solid, about 1 hour longer.
2. Place pan with frozen pops on work surface; carefully fold back foil over each cup without dislodging stick. Spoon lemonade into cups, dividing equally (scant 3 tablespoons each). Reseal foil. Freeze until lemonade layer is solid, about 2 hours.
3. Place pan with frozen pops on work surface; carefully fold back foil over each cup without dislodging stick. Spoon blueberry mixture into cups, dividing equally (generous 3 tablespoons each). Reseal foil. Freeze until pops are frozen solid, about 8 hours. (Can be made 2 days ahead. Keep frozen.)